Value of heart rate variability and sympathetic skin response in differential diagnosis of Parkinson's disease

Objective: To evaluate the value of heart rate variability (HRV) and sympathetic skin response (SSR) in differential diagnosis of Parkinson's disease (PD). Methods: We selected 36 PD, 17 essential tremor (ET) and 59 Parkinsonism-Plus (PD-plus) patients diagnosed in our department. We recorded HRV during the period of quiet breath, deep breath and Vasaval as well as SSR incubation period of the upper limbs and lower limbs. Results: (1) During the period of quiet breath, HRV decreased significantly in PD group compared with that in ET group (P<0.05), and abnormality rate of HRV in PD group was higher than that in ET group. HRV did not significantly differ between PD and PD-plus. HRV did not significantly differ among the three groups during the period of deep breath and Vasaval. (2) SSR incubation period showed no significant difference among PD, PD-plus and ET groups. (3) The specificity and sensibility of HRV in PD and PD-plus differential diagnosis were 22.8% and 82.6%, while for PD and ET differential diagnosis the values were 66.9% and 82.6%. The specificity and sensibility of SSR in PD and PD-plus differential diagnosis were 39.0% and 52.6%, 29.4% and 52.6%, respectively, for PD and ET differential diagnosis. Conclusion: Compared with those in ET patients, HRV in PD patients decreases and HRV abnormality rate increases. HRV is of great value in differential diagnosis of PD and ET but not in differential diagnosis of PD and PD-plus. Determining SSR incubation period does not have much value in differential diagnosis of PD, PD-plus and ET.